1) Field of the Invention
The present invention relates to a screw used exclusively for the wooden plate, more especially a screw structure that reduces turning friction for an easy and secured fastening.
2) Description of the Prior Art
The conventional structure of a wood screw usually comprises a shank with a screw head and threads disposed along the shank. Such wood screw generally has rounded side ridges with larger surfaces creating bigger contact friction and requires large turning torque to drive in to wooden plate completely. Manufacturers have developed screws with polygonal threads to reduce their contact surfaces and friction. Although such screws can improve the shortcomings of the round threads, the pointed tips thereof continue to cut through the object to be secured during screwing. Therefore, to reduce the fiction through only the polygonal threads is insufficient. It is necessary to provide a screw structure capable of increasing the efficiency, enhancing the practical value of the product and exclusive for fastening wooden plates. It is also the motive of the innovation of the present invention.
The primary objective of the present invention is to provide an improved screw structure to be used exclusively for fastening wooden plates and the bottom end thereof can make a pointed or planar cut at a certain degree so as to reduce the friction and to enable a more efficient and smoother fastening.
The aforesaid screw structure comprises a shank with a screw head at the top end and square edged threads arranged helically along the shank; wherein, between the third and the fourth threads from the bottom end of the screw, a shaft flange is positioned parallel or slanted to the longitudinal axis of the shank. When the screw is driven, the shaft flange makes a pointed or planar cut the object to be secured and thereby reduces friction.
The abovementioned screw structure positions the shaft flange between the upper and the lower rims of the third and the fourth threads.
The abovementioned screw structure has a shaft flange disposed at the bottom end of the shank in a convex trapezoid shape to facilitate a pointed or planar cut.
To enable a further understanding of the main features and innovation of the invention herein, the brief description of the drawings below is followed by the detailed description of the preferred embodiments.